Hey everyone, I was reviewing some of the projects I’ve worked on over the past year, and I noticed something interesting: I almost never use Python’s @dataclass anymore. Not because it’s bad. In fact, dataclasses are still a great feature of the language. But as my projects have grown more complex, especially with tools like FastAPI, Pydantic, and SQLAlchemy, I’ve found that dataclasses just… don’t fit the way I design software anymore. In my latest video, I dive into this in detail. You’ll...
8 days ago • 1 min read
Hi there, You’ve probably heard that serverless is the easiest way to deploy code to the cloud. And on the surface, it is. With Google Cloud Functions, you can literally deploy a simple Python function like this: def hello(request): return "Hello from Cloud!" A few lines of code. No servers. No infrastructure. But... there are quite a few limitations: No FastAPI or async support One route per function requirements.txt only, no pyproject.toml Cold starts for large dependencies No custom...
15 days ago • 1 min read
Hey there, Heard of MCP? It stands for Model Context Protocol: an open standard that lets AI models like Claude or ChatGPT connect to real tools and data. In my latest video, I explain what MCP actually is, and show a working example where Claude can search YouTube videos using MCP. In the video you’ll learn: Why AI models can’t just call your API How MCP bridges that gap Two ways to structure your MCP integration Happy coding! Cheers, Arjan # News Upcoming Python Documentary CultRepo...
22 days ago • 1 min read
Hi there, We all use def to define functions in Python. But did you know there are at least 7 other ways to do it? Some of them are useful. Some are questionable. And the last one is so ridiculous, it might crash your interpreter. In this week’s video, I walk through each method, explain how it works, why you should use it (or not), and what it teaches us about how Python works under the hood. This was a really interesting topic to explore. I learned a lot from it and I hope you will too....
29 days ago • 2 min read
Hi there, Functional programming in Python can be elegant… but not always. ⚠️ In this week’s video, I walk through four common scenarios where replacing for loops with map() and filter() actually leads to worse code. Not just less readable—but also harder to debug, more error-prone, and sometimes even misleading. We’ll dive into: Exception handling that becomes a mess inside a lambda Side effects (like writing to files) that violate functional principles Nested logic that turns into...
about 1 month ago • 1 min read
Hi there, What’s in my stack? Python, TypeScript… and one wooden robot. 🤖 You might not know this, but before ArjanCodes was a channel, it was a pile of ideas held together by duct tape and Google Docs. Now? We’ve got a full ecosystem: static websites on Astro, backend automations in Python, our own SDK, and a business portal for team licenses—all deployed with GitHub Actions and a sprinkle of serverless. ⚡ In this week’s video, I give you a behind-the-scenes tour of our real tech stack—no...
about 1 month ago • 2 min read
Hi there, You ever look at some Python code and think, “Wait… why did we do it like this?” This week’s video is all about the Python anti-patterns that sneak into our codebases—sometimes looking clever, sometimes just copied from bad tutorials. But they can seriously hurt long-term maintainability. 🚨 I walk through 10 real-world examples, from using exceptions as control flow to awkward class structures, and even show how hardcoding UI strings can make your app a localization nightmare. Have...
about 2 months ago • 1 min read
Hi there, I’m emailing you from prison. 🚨 No, not like that. The new ArjanCodes office is inside a 19th-century prison in Utrecht. And it’s actually… amazing. The cells are now offices, the vibe is creative, and it’s got just the right kind of gloominess for video production (because direct sunlight and camera lenses don’t mix). In this week’s video, I take you on a little tour of the space and talk about what’s ahead for the channel. After a year of scaling down, I’m finding more balance—and...
about 2 months ago • 2 min read
Hi there, We all know type hints can catch bugs before runtime. 🐛 But what if I told you they’re also one of your best tools for designing better software? In this week’s video, I show how type hints can lead to smarter choices about inputs, outputs, and even class structure — all without adding complexity. It’s the kind of thinking that leads to better architecture and fewer “why did I do this?” moments later on. 😌 And yes, I also drop a few tips you’ve probably never heard about inputs and...
2 months ago • 2 min read